Provide an option to disable prompt face configs

[casouri]

There is no easy way to disable them outside aweshell.el right now.

If I change :inherite attribute of any epe faces,
it will not take effect because you set :foreground in aweshell.el.

[manateelazycat]

i will remove face from source code

[manateelazycat]

8000e82 has remove face settings code